The Emergence of Mass Timber Construction: Technology, Safety, and Sustainability

Mass timber construction uses solid wood panels, beams, and columns as primary structural elements. They are often manufactured off-site for load-bearing wall, floor, and roof construction. Mass timber is generally lighter than traditional materials like steel and concrete. Mass timber products are made of compressed layers of wood that result in sturdy, load-bearing structural parts that may be assembled into panelised components. Usually, lamination, fasteners, or adhesives are used to form them.

Products of mass timber usually include cross-laminated timber (CLT), dowel-laminated timber (DLT), laminate strand lumber (LSL), glue-laminated timber (GLT), laminated veneer lumber (LVL), parallel strand lumber (PSL), and nail-laminated timber (NLT). These are the foundation of tall-wood building systems and can be used in various applications. Mass timber has gained popularity due to its various advantages, as it is an alternative to traditional construction materials like steel and concrete. Its advantages are strength and performance, sustainability, fire resistance, speed of construction, aesthetics, design flexibility, seismic performance, and great acoustic and thermal performance.

Technology

Technological advancement is one of the main reasons for the emergence of mass timber construction. Software like BIM and CAD are crucial tools for designing mass timber structures. They help to create detailed 3D models, optimise material usage and address other issues before the construction begins. Machines like CNC help to cut mass timber components according to specifications precisely. These machines work efficiently and accurately to ensure during assembly. Mass timber construction often involves prefabrication, where the components are manufactured off-site in controlled factory environments. Panelised construction systems involve the use of pre-made mass timber wall, floor, and roof panels that are assembled on-site. 

Mass timber components are connected using specialised hardware and connectors designed for timber-to-timber or timber-to-steel connections. Mass timber construction requires well-fire-protecting systems like fire-resistant coatings and other techniques which enhance their performance. Thus, engaging with experienced professionals and consultants in mass timber construction is crucial to ensure the effective implementation of these technologies.

Safety

As technology has advanced in construction, safety factors must also be considered. Mass timber construction is considered safe when proper design, engineering, and adherence to building codes and regulations are followed. 

Mass timber products have been extensively tested and engineered to meet fire safety standards. They also undergo rigorous engineering, testing, and quality control measures to ensure structural integrity. Advanced computer modelling and analysis techniques are used to assess mass timber structures’ load-bearing capacity, deflection, and stability. Skilled construction teams with expertise in mass timber construction techniques are crucial for safely and accurately assembling mass timber components. Proper handling, connection details, and installation techniques are essential to maintain the structural integrity of the building. 

Mass timber structures have demonstrated good performance in seismic events. Wood has inherent flexibility, allowing it to absorb and dissipate energy during earthquakes. Compliance with seismic design codes and regulations is important for ensuring the safety of mass timber structures in earthquake-prone regions.

Sustainability

Mass timber construction is widely recognised as a sustainable practice. The wood used in mass timber construction is derived from responsibly managed forests. Sustainable forestry practices ensure the replenishment and regeneration of the timber resource, making it a renewable material. Carbon sequestration happens in the mass timber products as carbon remains stored there as trees absorb the carbon dioxide from the atmosphere. Mass timber products require less energy than traditional construction materials like concrete and steel. Wood processing and manufacturing have lower energy requirements, resulting in reduced greenhouse gas emissions during production. 

Mass timber structures can help maintain comfortable indoor temperatures, reducing the need for excessive heating or cooling and making them energy efficient. This energy efficiency can lead to reduced energy consumption and lower operating costs over the lifetime of the building. Mass timber components are often prefabricated off site, resulting in less construction waste, reducing overall waste. Precise manufacturing and assembly processes reduce material waste, and offcuts and leftover timber can be recycled or repurposed. This further leads to a circular economy as it leads to efficient usage of resources. The demand for mass timber supports sustainable forest management practices. Responsible forest management ensures forests’ long-term health and productivity, preserves biodiversity, and protects natural habitats. Mass timber production creates aesthetic, warm, and inviting spaces and positively impacts the occupants. 

Birdport House

Birdport House is an outstanding example of how mass timber has been used since then. This project replaced an original housing 21 flats with two new joined blocks providing a total of 41 new homes. The house was designed by Karakusevic Carson Architects and was completed in around 2011. The project represents the high usage of cross laminated timber (CLT). The unique properties of CLT helped to make the structure load bearing. As CLT spreads its weight along a line, it was possible to double the height of the structure, increasing its load by 10% only. The project later received Housing Design Awards 2012: Best Resident Engangement Program, Best use of GLA Standards, and RIBA Awards 2012 shortlist.

References

Good, W. f., 2016. Wood for Good. [Online]
Available at: https://woodforgood.com/case-studies/bridport-house

Oval, R. O., 2023. Naturally.wood. [Online]
Available at: https://www.naturallywood.com/topics/mass-timber/

Smith, C., 2023. CD Smith Construction. [Online]
Available at: https://www.cdsmith.com/mass-timber-construction